Jump to content

Think my engine is blown?!

Recommended Posts

Ok, I have an 09 crf450r was out to the track today bike was running perfect get into a corner power out and it just cuts out?! Went to try and start it up and nothing... It still turns over fine but she'll back fire every few kicks. I'm just beginning to get into wrenching so I still have tons and tons to learn and I'm wondering if maybe the engine failed? Would it still turn over freely? Wouldn't she be seized up? Or do you think maybe it's the plug? I had a similar problem last year which involved the plug. The plug had spark but still wouldn't go so I threw and new plug in and the thing fired up and ran perfect until now. Just looking for some help!!!

Share this post


Link to post
Share on other sites
12 minutes ago, DJAY18 said:

Ok, I have an 09 crf450r was out to the track today bike was running perfect get into a corner power out and it just cuts out?! Went to try and start it up and nothing... It still turns over fine but she'll back fire every few kicks. I'm just beginning to get into wrenching so I still have tons and tons to learn and I'm wondering if maybe the engine failed? Would it still turn over freely? Wouldn't she be seized up? Or do you think maybe it's the plug? I had a similar problem last year which involved the plug. The plug had spark but still wouldn't go so I threw and new plug in and the thing fired up and ran perfect until now. Just looking for some help!!!

If you can kick it it's not seized.  Sounds electrical to me but who knows? You should check easy stuff first like the plug, coil wire (mine had rubbed half thru from the valve cover), connections, etc.  Get a manual.  Were there any noises before it stopped?

If it's something with the FI hopefully someone more knowledgeable than me will chime in.

  • Like 1

Share this post


Link to post
Share on other sites

No there was no noise what so ever she just stalled out and would not start anymore.. It was as if I dumped the clutch and stalled but I was already on the gas out of the corner and than she just died on me.. 

Share this post


Link to post
Share on other sites
2 hours ago, DJAY18 said:

No there was no noise what so ever she just stalled out and would not start anymore.. It was as if I dumped the clutch and stalled but I was already on the gas out of the corner and than she just died on me.. 

I think other than easy stuff, maybe an ohm meter and manual and start testing.  

Share this post


Link to post
Share on other sites

Yeah I'm gonna start with a new spark plug. Then go to the fuel pump. Hoping I can get this figured out soon. The season just started here and I'm already down..

Share this post


Link to post
Share on other sites
2 hours ago, HeavyRotation said:

Biff hasn't been around so I'm gonna step in here with the gratuitous, "should've bought a two stroke!"

Biff may be right. These dang thinks are expensive!

  • Like 1

Share this post


Link to post
Share on other sites
4 minutes ago, buildr102 said:

My 14 did the same thing, checked compression it was low. The piston was cracked. Wiseco HC 13.5/1

Was it an expensive fix? im planing on doing the work myself if it is the top end.

Share this post


Link to post
Share on other sites

Also what's you're thoughts on the HC piston I'm only running 91 and I'm just a wknd warrior with the odd race here and there. If I were to use vp t4..is the HC worth it or just gonna end up costing me rebuild more frequently? 

Share this post


Link to post
Share on other sites

No need to go hc, unless your rebuilding every 20 hrs. $ not too bad, wonder if the 2017 stock piston would work it's hc

Share this post


Link to post
Share on other sites
12 minutes ago, buildr102 said:

No need to go hc, unless your rebuilding every 20 hrs. $ not too bad, wonder if the 2017 stock piston would work it's hc

I can pick up a wiseco top end kit here in Canada for $234 and a top end gasket kit for $74 cylinder will need a light hone as well so I'm gonna get a dealer to do it don't want to mess that up! That's if there isn't much damage.. I've never had a piston crack on me before if that's is what happened. Just getting ready to pull it apart right now 

  • Like 1

Share this post


Link to post
Share on other sites

Doesn't sound like your engine is blown due to you being able to turn it over with the kick starter.  Try trouble shooting it first before disassembling the engine.  It could be something simple like a clogged fuel filter that needs to be replaced.  The fuel filter was upgraded in 2010 so when you need to replace the 09 it's been super-ceded with the 10 part #.

Try this first.

 09-10%20CRF450r%20trouble%20shoot%20star

Edited by H4L

Share this post


Link to post
Share on other sites
7 minutes ago, H4L said:

Doesn't sound like your engine is blown due to you being able to turn it over with the kick starter.  Try trouble shooting it first before disassembling the engine.  It could be something simple like a clogged fuel filter that needs to be replaced.  The fuel filter was upgraded in 2010 so when you need to replace the 09 it's been super-ceded with the 10 part #.

Try this first.

 09-10%20CRF450r%20trouble%20shoot%20star

Ok, thanks man! Bike has 96 hours on it tho and I bought it used do you think I should take a look at the piston anyway just to be on the safe side? 

Share this post


Link to post
Share on other sites

Yes.  At 96 hrs. I'd definitely change the piston & inspect the head as well as the bottom end while it's apart.

Share this post


Link to post
Share on other sites

So it kicks over and backfires occasionally? Could the TPS screw have come loose? Those do have an adjustment. If it's backfiring it has to be getting a spark. It should have a mark o the top from the factory but is calibrated with a meter. See if you can wiggle it.

Share this post


Link to post
Share on other sites

My gut instinct told me to take it apart.. Piston cracked.. Right across the centre 

image.jpeg

Share this post


Link to post
Share on other sites

My gut instinct told me to take it apart.. Piston cracked.. Right across the centre 

Share this post


Link to post
Share on other sites

So cylinder still has a nice cross hatch pattern no scoring what so ever and no up and down play in crank everything seems pretty solid. So I'm gonna pick up a wiseco piston kit once I get a chance. Should I bring the cylinder in for a light hone as well? 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×